Common Vitamin Deficiencies in Pets: What Are They & What to Do

Most dogs and cats get the vitamins they need from a complete and balanced diet. But an unbalanced diet or a health condition that affects how nutrients are absorbed can sometimes lead to a deficiency.

The signs aren’t always obvious. Changes in appetite, energy, weight or coat quality can have many causes, so a vitamin deficiency isn’t something you can reliably identify at home. Here’s what may put a pet at risk and when to speak with your veterinarian.

Why Do Vitamin Deficiencies Occur in Pets?

A deficiency is less likely when a pet eats a complete and balanced food suited to their species and life stage. It may become a concern when they aren’t getting enough of a nutrient from their diet or their body has trouble absorbing or using it.

Potential reasons include:

•  A homemade or restricted diet that hasn’t been formulated to meet all of the pet’s nutritional needs

• A digestive condition that interferes with nutrient absorption

• A health condition that changes nutritional needs

• Ongoing poor appetite or difficulty eating

• Food that isn’t appropriate for the pet’s species or life stage

If you feed a homemade or highly restricted diet, ask your veterinarian or a veterinary nutrition specialist to review it. Pets with ongoing digestive symptoms may also need an assessment to find out whether they’re absorbing nutrients properly.

Which Vitamin Deficiencies Can Affect Pets?

Different vitamins have different jobs in the body. Which deficiency a veterinarian might investigate depends on your pet’s diet, symptoms and medical history.

• Vitamin A supports vision, growth, immune function and skin health. Too little can cause problems, but too much can also be harmful.

• B vitamins help the body use energy and support normal nerve function. Vitamin B12, also called cobalamin, may be low in some dogs and cats with intestinal or pancreatic conditions.

• Vitamin D helps regulate calcium and phosphorus for healthy bones. Dogs and cats rely on their diet for vitamin D, but excess amounts can be toxic.

• Vitamin E helps protect cells from damage. A deficiency may be associated with an unbalanced diet or difficulty absorbing fat.

These examples aren’t a checklist for choosing a supplement. Your veterinarian can determine whether a particular nutrient needs further investigation.

Signs of a Potential Nutritional Deficiency

Signs can vary significantly depending on the nutrient involved and the underlying cause. Possible changes may include:

• Low energy 

• Changes in appetite

• Unexplained weight loss

• Poor coat quality or skin changes

• Digestive problems

• Changes in growth or development

• Muscle weakness or mobility changes

These symptoms are not specific to vitamin deficiencies and can occur with many other medical conditions. Avoid diagnosing a deficiency based on symptoms alone.

How Are Vitamin Deficiencies Confirmed?

If you are concerned about your pet's nutrition, start with your veterinarian.

Your veterinarian may review your pet's diet, medical history, medications, and symptoms before recommending blood work or other diagnostic testing. Identifying the underlying cause is important because simply adding a vitamin may not address the reason a deficiency developed.

When Might a Pet Need a Vitamin Supplement?

If your veterinarian identifies a deficiency or a specific nutritional need, they may recommend a diet change, a targeted supplement or treatment for an underlying condition. The right approach depends on the pet and the nutrient involved.

Before adding a supplement, check what’s already in your pet’s food and any other products they take. Giving several products containing the same vitamin can lead to excessive intake. Follow your veterinarian’s advice on the product and amount rather than using a human vitamin or choosing a supplement based on symptoms alone.

Pets Drug Mart carries vitamins and supplements for pets that can be used as part of a veterinarian's recommended care plan. 

Nutrition Is About Balance

Vitamins are essential to your pet's health, but the goal is balance rather than simply adding more.

For most healthy dogs and cats, a complete and balanced diet provides the vitamins they need. If your pet’s diet is limited or you’ve noticed a change in their health, speak with your veterinarian before adding a supplement. They can help determine whether nutrition is part of the issue and what support, if any, makes sense for your pet. If a supplement is recommended, explore Pets Drug Mart.